- WASHINGTON (Reuters) - Using
crops genetically engineered to resist weedkillers might harm birds --
not because the genetic changes are harmful but because killing weeds means
less food for birds, researchers said on Thursday.
- Some farms where such crops are used could see a 90 percent
drop in the number of weeds -- a boon to farmers but bad news for hungry
birds, Andrew Watkinson of the University of East Anglia in Norwich, England,
- Watkinson and colleagues used a computer model to predict
the effects that planting a weedkiller-resistant sugar beet would have
on a weed known as lamb's quarters or fat hen (its scientific name is Chenopodium
album), whose seeds are a major food source for skylarks.
- ``We predict that weed populations might be reduced to
low levels or practically eradicated, depending on the exact form of management,''
they wrote in their report, published in the journal Science.
- ``Consequent effects on the local use of fields by birds
might be severe, because such reductions represent a major loss of food
- They said the effects on overall bird populations would
depend on whether a few large farms used the genetically modified (GM)
crops in just a few places, or if such crops were planted by many different
- ``These results probably apply widely to other crops,
weeds, and seed-eating birds,'' Watkinson told Science.
- But he stressed the results would be seen as a result
of any weed management practice. It is just that using GM crops is a particularly
effective way to get rid of weeds, he said.
- Watkinson said bird populations in Britain have fallen
by up to 90 percent in the last 25 years.
- ``It seems likely that the widespread introduction of
herbicide-tolerant crops will result in further declines for many farmland
birds unless other mitigating measures are taken,'' he said.
- Monsanto Replies
- Monsanto Corp., which makes the Round-Up Ready soybean
genetically modified to resist its herbicide of the same name, was quick
to issue a response to the study.
- ``It is important to understand that this is not an issue
of biotechnology,'' the company, a division of Pharmacia Corp., said in
- ``It is an issue of weed control, whether through biotechnology
or other methods. This mathematical model, and any conclusions drawn from
it, must be viewed with caution because it does not reflect real farming
- But Watkinson had pointed out that using a computer model
saved having to wait for years of field studies.
- One argument made in favor of GM crops is that they can
allow farmers to use less weedkiller than they normally would, because
they can kill off weeds with one big dose while leaving crops undamaged.
- ``Data from other scientists who have conducted field
studies on herbicide-tolerant sugar beets has shown that herbicide-tolerant
plants allow farmers to maintain weeds longer in sugar beet fields, which
could offer greater resources at a time of year when food for birds is
scarce,'' Monsanto argued.
- ``Agricultural practices that improve the yield per acre
actually prevent additional land from coming under cultivation, preserving
the best wildlife environments in their natural state and protecting indigenous
habitats for birds and other wildlife.''
- GM crops have been attacked by environmental groups,
which have cited studies that suggest that Monarch butterflies can be harmed
by pollen from GM plants.
- Most recently, Iowa State University researchers said
Monarch butterfly caterpillars were seven times more likely to die when
they ate milkweed plants carrying pollen from Bt corn, which produces a
pestkilling protein taken from bacteria known as Bacillus thuringiensis.
- Other researchers have attacked this and similar studies,
saying they do not reflect real-world conditions.
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